CBSE NCERT Notes for Class 9 Science Chapter 16 IMPROVEMENT IN FOOD RESOURCES

NCERT Notes for Class 10 Science IMPROVEMENT IN FOOD RESOURCES

CBSE Class 10 Science notes will assist students in studying the topic thoroughly and clearly.

These CBSE Class 10 Science notes were written by subject experts who made the study material very basic, both in terms of language and format.

NEED FOR IMPROVEMENT IN FOOD RESOURCES IN INDIA

India is a densely populated country. Its population exceeds one billion and continues to increase. We will soon need more than a quarter of a billion tonnes of grain per year to feed our rising population. 

This need may be met by increasing agricultural operations, but India is already densely populated. As a result, we have no space to expand the area under cultivation. As a result, it is vital to boost our agriculture and livestock production efficiency.

To fulfil these demands, the green revolution has aided in the expansion of food grain production. The white revolution resulted in an increase in milk supply. Scientific research has also aided in the advancement of these revolutions.

Our natural resources are being utilised more aggressively as a result of these revolutions. As a result, there is a greater risk of causing damage to our natural resources and ecosystem, as well as altogether disrupting its balance.

We should expand food production without degrading or disrupting the environment’s delicate balance. This may be accomplished by adopting sustainable agricultural and animal husbandry techniques.

Obtaining high yields from a farm is simple when scientific management approaches are used. It includes mixed farming, intercropping, and integrated agricultural methods (e.g., agriculture operations in conjunction with livestock, poultry, fisheries, and beekeeping).

TYPES OF CROPS

Human beings plant crops for their own advantage. Crops of importance include the following:

Cereal crops : These plants are planted to provide daily energy needs, for example, wheat, rice, maize, millets, and sorghum (which supply carbohydrates to meet daily energy requirements).

Pulse : These plants are grown to provide protein requirements, for example, gramme (chana), pea (matar), black gramme (urad), green gramme (moong), pigeon pea (arhar), and lentil (masoor).

Oilseed crops : These plants, such as soybean, peanut, sesame, castor, mustard, linseed, and sunflower, supply vital fats and oils.

Vegetables, spices and fruits : These plants, such as cabbage, onion, and pepper, provide a range of vitamins and minerals in small amounts of protein, carbohydrates, and lipids.

Fodder crops : These plants, such as berseem, oats, or sudan grass, are produced for cattle feed. Each crop needs a unique set of climatic variables, temperature ranges, and photoperiods to grow and complete its life cycle. The length of sunlight is essential for plant growth and blooming. 

Additionally, plants need sunlight to carry out their photosynthesis function (photoperiods).

CLASSIFICATION OF CROPS

Crops are classified according to season. Crops grown in Kharif These crops are cultivated from June through October during the hot and wet season. Paddy, soybean, pigeon pea, maize, cotton, green gramme, groundnut, black gramme, and here are just a few examples.

Crops rabi These crops are cultivated throughout the dry and winter months of November to April. Wheat, gramme, pea, mustard, linseed, and barley are just a few examples.

IMPROVEMENT IN CROP YIELD

The agricultural practises used to boost crop production may be classified into three stages:

The first step is the seed selection. The second is agricultural plant cultivation. The final objective is to prevent crop loss when it is being grown and harvested.

Thus, the key groups of activities affecting agricultural yields may be categorised as follows:

1. Crop production management 
2. Crop variety improvement
3. Crop protection management. 

CROP VARIETY IMPROVEMENT

The primary objective of this approach is to identify a variety of crops that can thrive in a variety of environments such as high soil salinity, various climatic conditions, and limited water availability (drought and flood).

To get acceptance for new crop kinds, it is vital for the variety to provide good yields under the various situations found in various places. Farmers should be given high-quality seeds of a specific variety to do this. The seeds should be identical in kind and germinate under the same conditions.

Crop varieties or strains may be chosen for a variety of characteristics such as disease resistance, fertiliser response, product quality, and high yields. A new variety created with all of these characteristics is extremely desirable.

WAYS FOR IMPROVEMENT IN CROP VARIETY

There are two different methods for integrating desired characteristics into crop types. These include the following:

• Hybridisation :

• Interspecific: The cross is formed by two planes belonging to distinct species within the same genus.

• Intervarietel : The cross is produced between two plants belonging to two distinct crop kinds. It is the most often used method in plant breeding.
• Intergeneric : The cross is formed by planes of distinct genera.

2. Genetically Modified Crops : 

It entails altering crop planes in order to increase production, quality, and sustainability. Genetic modification imparts desirable characteristics to the crop.

FACTORS OF CROP VARIETY IMPROVEMENT

The following are some of the reasons for crop variety improvement.

• Higher yield : Variety enhancement is carried out to boost the crop’s production per acre.

• improved quality : The definition of quality is different for different crops. For e.g. baking quality is important in wheat, protein quality in pulses, oil quality in oilseeds and preserving quality in fruits and vegetables. 

• Biotic and abiotic resistance : Crop productivity is significantly impacted by biotic stresses (diseases, insects, and nematodes) and abiotic stresses (drought, salt, water logging, heat, cold, and frost). Varieties that are resistant to such circumstances are always selected since they contribute to crop yield improvement.

• Change in maturity duration : A crop’s economic value increases with the shorter time or interval between planting and harvesting. It enables farmers to cultivate several crops throughout the year. Additionally, it minimises agricultural production costs. Harvesting is facilitated by uniform maturation. Additionally, it minimises crop losses.

• Wider adaptability : Crop production may be stabilised by developing varieties that grow and adapt to a variety of situations. As a result, a single variety may be produced in places with varying environmental circumstances.

• Desirable agronomic characteristics : These features indicate that plants are growing and producing more. Such plants are favoured above others, for

for example, tallness and profuse branching are desired features for fodder crops. In cereals, dwarfism is preferred.

CROP PRODUCTION MANAGEMENT

It entails the management of many elements of crop production in order to maximise yield. It requires an in-depth understanding of almost every facet of crop production.

It is the availability of money or financial resources that enables farmers to adopt new farming methods and agricultural technology. There is a relationship between increased inputs and increased yields. The farmer’s buying power for inputs dictates the planting scheme and production techniques. 

Thus, manufacturing processes may be classified into three categories: zero-cost, low-cost, and high-cost. Crop production management includes nutrition control, irrigation management, and cropping pattern management.

NUTRIENT MANAGEMENT

Plants, like animals, need nutrients for growth and development. Nutrients are inorganic elements that plants get from the air, water, and soil. Plants need sixteen basic nutrients.

Essential plant nutrients are classified into two categories:

• Micronutrients: There are seven nutrients in all. They are needed in smaller quantities by plants. Iron, manganese, boron, zinc, copper, molybdenum, and chlorine are among them.
• Macronutrients: There are six nutrients in all. They are used in large quantities by plants, which is why they are referred to as macronutrients. Nitrogen, phosphorus, potassium, calcium, magnesium, and sulphur are the elements.

Any of these nutrient deficiencies impacts physiological processes in plants, including reproduction, growth, and disease susceptibility. Manure and fertilisers may be used to provide nutrients to the soil. It contributes to agricultural yield increases.

Manure : Natural fertilisers are manures. These are the organic molecules generated during the breakdown of animal excrement and airplane garbage. It provides trace amounts of nutrients to the soil.

1. Compost and vermicompost : Composting is the process through which agricultural waste products such as livestock excreta (cow dung, for example), vegetable waste, animal refuse, domestic garbage, sewage waste, straw, and eliminated weeds are digested in pits.

• Compost is a great source of organic materials and nutrients.
• Vermicomposting is the method of preparing compost by using earthworms to accelerate the breakdown of plant and animal waste.

1. Green manure : Certain plants, such as sunhemp or guar, are grown and mulched by ploughing into the soil prior to seed planting. These green plants decompose and provide green manure.

It contributes to the soil’s nitrogen and phosphorus content growth. Additionally, it aids in improving the soil’s moisture, aeration, and crumb structure.

Advantages of manure are as follows: 

1. Manure provides nutrients and organic materials to the soil (called humus )
2. Manure improves soil fertility and mitigates the soil-damaging impacts of herbicides and insecticides.
3. It contributes to soil structure improvement by enhancing the water retention capacity of sandy soil. In clayey soils, a high organic matter content aids in drainage and prevents water logging.
4. We can safeguard the environment from excessive fertiliser usage by using biological waste material (manure).
5. Manure contributes to the recycling of agricultural waste.

Fertilisers: They are plant nutrients that are manufactured commercially. They provide the soil with Nitrogen, Phosphorus, and Potassium (NPK).

The benefits of fertilisers:

1. They are readily accessible, simple to use, and easy to store.
2. They contribute to the increased yields related to high farming.
3. They are used to encourage healthy vegetative growth (leaves, branches, and flowers) and to ensure the development of healthy plants.

Disadvantages of fertilisers : 

1. They must be used with caution in terms of correct dosage, rime, and attention to pre- and post-application precautions in order to be entirely effective. Excessive usage of fertilisers, for example, might pollute water since they are washed away when they are not properly absorbed by the plants owing to over-irrigation.
2. Because organic matter in the soil is not regenerated, the continuous application of fertilisers may decrease soil fertility. As a result, the usage of fertilisers harms soil microorganisms.
3. They are beneficial in the short term. Thus, in order to achieve optimal crop yields, the short-term advantages of utilising fertilisers and the long-term

benefits of employing manure must be addressed in order to preserve soil fertility.

IRRIGATION

The method of distributing water to agricultural plants in fields through canals, reservoirs, wells, tubewells, and so on is known as irrigation. Agricultural practises in India are rain reliant. The success of a crop is mostly determined by timely monsoons and enough rainfall throughout the growing season. 

The predicted yields of any crop may be boosted by ensuring that water is delivered to the crops at the appropriate stages and in the requisite quantities. Farmers rely on natural resources such as ponds, wells, canals, and so on to irrigate their farmlands.

The following are some regularly utilised irrigation methods based on the kind of water resources available for agricultural purposes:

Wells : They are built anywhere there is groundwater for irrigation. They are classified into two types:

• Excavated wells : Water is extracted from water-bearing strata.
• Tube wells : Using pumps, water may be pulled from deeper strata.

Canals : They are a complex and widely used way of obtaining water from reservoirs such as dams or rivers.

The main canal is further subdivided by branches that have disrriburaries to irrigate land.

River Lift Systems : This strategy is utilised when canal flow is limited or irregular owing to a lack of reservoir release. Water is taken straight from rivers here to assist irrigation in river-side areas.

Tanks : These are tiny reservoirs for storage of water. They collect and assess runoff from smaller catchment areas.

Modern Techniques : These are new projects aimed at increasing agricultural water supply by supplementing groundwater. They are as follows:

• Rainwater harvesting
• Watershed development

CROPPING PATTERNS

It entails growing crops in order to get the most out of a given plot of land. It lowers the likelihood of crop failure, illness, and other problems.

Crops may be cultivated in a variety of methods for this purpose. Among them are:

Mixed Cropping : In this practice, two or more crops are produced on the same plot of land at the same time. For example, wheat+gram, wheat+mustard, groundnut+sunflower, and so forth. The following are some of the benefits of mixed cropping :

• Increases soil fertility.
• The probability of complete crop failure owing to erratic monsoon conditions is lowered.
• Provides some protection against crop failure.

Intercropping : In this method, two or more crops are grown in a certain pattern on the same field at the same time. A few rows of one crop are alternated with a few rows of another. The crops are chosen based on their nutritional needs. 

Two crops must have distinct nutritional needs. For example, soybean + maize, finger millet (bajra) + cowpea (lobia), and so forth.

The following are some of the benefits of intercropping:

• It guarantees maximal nutrient use and higher yields.
• It prevents pests and diseases from spreading to all plants of a single crop in a field.
• Both crops provide a higher return.

Crop Rotation : Different crops are produced on a plot of land in a pre-planned succession in this kind of operation. Crop mixture is determined by crop duration.

A crop is cultivated on a field, and then another crop is planted on the same field after it has been harvested. This may also come after a third harvest. The crop that will be planted following one harvest is determined by the availability of moisture and irrigation infrastructure.

CROP PROTECTION MANAGEMENT

Diseases and pests Crop protection management includes ways for reducing such infestations. If not handled in a timely manner, they may cause severe crop damage, resulting in the loss of the majority of the crops.

Crop risks include the following:

1. Weeds : These are the weeds in the farmed land. They battle for food, space, and light with the crops. Weeds consume nutrients and stifle crop development. As a result, they should be eradicated during the early phases of crop development to ensure a decent harvest. 

Weeds include Xanthium (gokhroo), Parthenium (gajar ghas), Cyperinm rotundus (mocha), Amaranthus, Chenopodium, wild oat, and others.

Weed control techniques include the following:

• Mechanical methods: uprooting, harrowing or manual weeding, ploughing, burning, and floods.
• Preventive methods : include proper seed bed preparation, timely crop planting, intercropping, and crop rotation.

1. Insect Pests : They have an impact on crop health and productivity. Plants are attacked by insect pests in the following ways:
   1. They sever the root, stem, and leaf, like locusts do.
   2. Aphids, for example, suck the cell sap from different areas of the plant.
   3. Shoot borer larvae, for example, burrow into stems and fruits.

Pests may be managed in a variety of methods, including: 

• the use of resistant cultivars.
• Summer Ploughing: During the summer, fields are ploughed deeply to eliminate weeds and pests.

1. Crop Diseases : Pathogens such as bacteria, fungus, and viruses cause plant diseases. These infections are found in and spread via the soil, water, and air.

Pesticides such as herbicides, insecticides, and fungicides may be used to control crop diseases. They are sprayed on agricultural plants in small quantities. Excessive usage of these compounds is detrimental to many plant and animal species.

It also pollutes the environment.

• Storage Of Grains : High losses in agricultural output may occur during grain storage.

The factors that contribute to such losses may be classified as follows:

• Rodents, fungus, insects, mites, and bacteria are examples of biotic forces.
• Abiotic factors: These include improper moisture and temperature conditions at the storage location.

These elements have the following effects on grains:

• Quality deterioration.
• Inadequate germinative ability.
• Fruit and vegetable discoloration.
• Weight loss.

All of this leads to low marketability and significant economic losses.

Among the preventative and control measures used during storage are the following: 

• Adequate grain storage may be achieved by proper warehouse treatment and management.
• Produce must be thoroughly cleaned before storing.
• Properly drying the product in the sun and then in the shade.
• Pests should be eliminated by fumigation. Chemical fumes are used to expose insect pests during fumigation.

ANIMAL HUSBANDRY

The scientific management of cattle is known as animal husbandry. It is the science of animal upbringing, feeding, breeding, disease management, and use. Cattle, goat, sheep, poultry, and fish fuming are examples of animal-based fuming.

NEED OF ANIMAL HUSBANDRY

• It is necessary to fulfil the rising demand for animal-based items such as milk, meat, eggs, leather, and so on, depending on population expansion and people’s living standards.
• It establishes rules for good animal care and a methodical approach to animal raising.

CATTLE FARMING

Cattle husbandry is practised in India for two reasons: milk and draught labour for agricultural tasks (such as tilling, irrigation, and carting).

Cattles in India are classified into two species:

• Bos indicus (cows) 
• Bos bubalis (buffaloes).

Cattles may be classified into two groups based on their work:

• Milch animals: These are milk-producing females, sometimes known as dairy animals.
• Draught animals: These are utilised for agricultural labour.

Breeds Of Cattle

• Indigenous or local breeds : They were chosen because of their strong resistance to co-disease, such as Redsindhi and Sahiwal.
• Exotic or non-native breeds : Jersey and Brown Swiss are chosen because of their lengthy lactation time. These two breeds may be crossed to produce animals with both desired traits.

Farm Management For Cattles 

Efficient farm management is critical for humane farming, improved animal health, and the production of clean milk.

The following are some farm management measures:

1. Cattles need proper washing and shelter facilities. ·
2. Animals should be brushed on a regular basis to eliminate filth and loose fur.
3. To protect the cattle from rain, heat, and cold, they should be housed in well-ventilated roofed shelters.
4. The cow shed floor should be slanted to keep it dry and easy to clean.

Food Requirements Of Cattles

Food is necessary for dairy catties for two reasons:

• For Maintenance: Food is essential to sustain the animal’s health.
• For Milk Production: During the lactation phase, the kind of diet is essential.

Animal feeds come in a variety of forms, including:

• Roughage: This is mostly fibrous and has little nutrients. Green fodder, silage, hay, and legumes are examples.
• Concentrates: These include little fibre. They have a high concentration of proteins and other nutrients. Cereals such as gramme and bajra are examples.

Aside from the items described above, various feed additives containing micronutrients improve dairy cow health and milk production. It should also be highlighted that cattle should be fed balanced feeds that include all nutrients in proportional proportions.

Diseases In Cattles

Cattles, like other animals, are afflicted with a variety of illnesses. These, in addition to causing mortality, also impair milk output. 

Cattle parasites are classified as follows: 

• External parasites : They dwell on the skin and cause skin problems, such as lice and mites. 
• Internal parasites : Worms that affect the stomach and intestines, as well as flukes that harm the liver, are among them. 

Cats may get infectious disorders from a variety of germs and viruses. Farm animals are immunised against a variety of viral and bacterial infections as a preventive precaution.

POULTRY FARMING

It entails raising domestic birds for the purpose of producing eggs and chicken meat. As a result, superior chicken breeds are created and farmed in order to produce layers for eggs and broilers for meat. 

Cross-breeding between Indian or indigenous (e.g. Aseel) and foreign or exotic (e.g. Leghorn) breeds has been beneficial in improving chicken breeds. 

These cross-breeding programmes aim to improve desired qualities like as: 

• Quality and quantity (number) of chicks. 
• Dwarf broiler mother for commercial chick production. 
• Capacity for summer adaptation/tolerance to high temperatures.
• Low upkeep required. 
• Reduction in the size of the egg-laying bird, allowing it to consume more fibrous and less expensive diets. This diet is made from agricultural byproducts.

Egg And Broiler Production

Broiler hens are provided vitamin-rich supplemental feed to promote rapid development and feed efficiency. 

To reduce mortality and preserve feathering and carcass quality, precautions are taken. They are raised as broilers and sold for meat in the market. Broilers and egg layers have distinct housing, nutritional, and environmental needs. 

Broiler diets are high in protein and low in fat. The levels of vitamin A and K in chicken feed are maintained high.

Maintenance Of The Shelter

The following activities are necessary for shelter maintenance: 

1. Proper cleaning and cleanliness of the shelter.
2. Maintaining the shelter’s temperature and cleanliness. 
3. Proper ventilation.
4. Disease and pest prevention and management.

Poultry Diseases And Their Prevention

Viruses, bacteria, fungus, and parasites cause a variety of illnesses in poultry fowl. They are also afflicted with nutritional deficiency problems. These illnesses may be avoided by: 

1. feeding poultry birds a nutritious diet. 
2. Proper shelter cleaning and sanitation.
3. Vaccinating poultry birds may help to reduce the spread of infectious illnesses. Proper immunisation may also help to prevent poultry losses during a disease epidemic.
4. Disinfectant spraying at regular intervals in the shelter.

FISH PRODUCTION

Humans may get animal protein at a low cost from fish. Fish production comprises both finned genuine fish and shellfish such as prawns and mollusks. 

There are two methods for acquiring fish: 

• Fishing for capture: It is a technique for collecting fish from natural resources. It is carried out in both inland and coastal seas.
• Culture fishery : It is a way of acquiring fish through pisciculture or fish farming. It is mainly done on inland and near-sea hores. 

Both approaches may be used to catch fish in both marine and freshwater habitats.

Marine Fisheries

In India, marine fisheries resources encompass 7500 kilometres of coastline and the deep waters beyond it. Many different types of fishing nets are used to catch marine fish from fishing boats. Pomfret, mackerel, tuna, sardines, and Bombay duck are popular marine fishes.

The following are examples of high-value marine fishes that originate in seawater: 

• Finned fishes: Mullets, bhetki, and pearl spots are all popular. 
• Shellfish : Seaweeds, prawns, mussels, oysters, and prawn Oysters are also grown for their pearls. 

Fish yield may be boosted by using satellites and echo sounders to locate enormous schools of fish in the open sea.

Inland Fisheries 

It encompasses both freshwater and brackish water fisheries. Canals, ponds, reservoirs, and rivers are examples of freshwater resources. Estuaries and lagoons are examples of brackish water resources, which occur when saltwater and freshwater mingle. 

These are also significant fish habitats. Capture fishing yields are low in such inland areas of water. As a result, aquaculture accounts for the majority of fish output from these resources. 

Fish cultivation is sometimes combined with rice crops. This provides adequate water for the paddy crop while also providing food for the fish.

Composite Fish Culture (Polyculture) : Fish production from a single species (monoculture) has a low yield and a greater cost. A composite fish culture involves the cultivation of 5 or 6 distinct fish species in a single pond. As a result, they do not compete for food with one another. As a result, it aids in more intense fish farming.

Advantages ofComposite Fish Culture : 

1. Both native and imported fish are utilised. 
2. Due to varied feeding preferences, the fish devour all of the food in the pond.
3. Because there is no competition for food, the fish production from the pond is great. Catla, for example, is a surface feeder, Rohu feeds in the intermediate zone of the pond, Mrigal and common carps are bottom feeders, and grass carp feeds on pond weeds.

Disadvantages ofComposite Fish Culture : Many fish only reproduce during the monsoon season. As a result, one of the biggest issues in fish farming is the scarcity of high-quality seed. 

To address this issue, fish are bred in ponds with hormone stimulation. It assures a steady supply of pure fish seed in the amounts required.

BEE-KEEPING

Honey is frequently utilised for a variety of reasons. As a result, its production has now evolved into an agricultural industry. Apiculture is the scientific term for it. It is the process of growing, caring for, and managing honeybees in order to get bee products such as honey, bee wax (used in medical preparations), and so on. Apiaries or bee farms are developed for commercial honey production.

Advantages Of Bee-Keeping

1. Requires a little investment. 
2. Offers a variety of goods such as honey (for eating or creating other products), wax (for medical and cosmetic preparations), bee venom, and so on.
3. Provides farmers with an extra source of revenue.
4. Improves agricultural output via improved pollination.

Honey

It is the primary product gained from apiculture. The value of honey is determined by the amount of pasture or flowers accessible to bees for nectar and pollen collecting. Honey flavour It is dependent on the amount of pasture and the kind of flowers available.

NCERT questions & answers from IMPROVEMENT IN FOOD RESOURCES

Question 1.

What do we get from cereals, pulses, fruits and vegetables ?

Answer:

Cereals: Mostly carbohydrates

Pulses: Mostly proteins

Fruits: Vitamins, minerals, organic acids.

Vegetables: Vitamins, minerals, small quantities of proteins, carbohydrates and oil.

Question 2.

How do biotic and abiotic factors adversely affect crop production?

Answer: Biotic factors are living organisms that reduce crop productivity due to either directly feeding on them

(e.g., insects, rodents) or causing diseases (e.g., nematodes, mycoplasmas, bacteria, viruses, fungi).

Abiotic factors are non-living components of the environment that affect growth of crop plants like excess of water (water-logging), scarcity of water (drought), salinity, heat, cold or frost. Water logging reduces aeration of soil which is harmful to growth and functioning of roots. In drought, water is not available to meet the requirement of the plants for transpiration, growth and photosynthesis. Frost, cold and heat reduce or inhibit metabolic activities and are, therefore, harmful.

Question 3.

What are the desirable agronomic characteristics for crop improvement? ( CCE 2015)

Answer: They are different for different crops.

Cereals should be dwarf but with large ears. Dwarfness makes their stem stronger. They can withstand the lodging effect of strong winds. Nutrient requirement is also less. Large ears produce more grains.

Legumes should have more pods which generally develop in relation to stem branching. Therefore, more branching and good foliage increase their productivity.

Fodder crops meant for feeding catde must have profuse branching, good foliage, juicy stems and large size.

Question 4.

What are macronutrients and why are they called macronutrients?

Answer: Macronutrients are essential elements required for growth and reproduction of plants. They are called macronutrients because they are required in larger quantities forming more than 1 mg per 1 gm of dry matter.

Question 5.

How do plants get nutrients ?

Answer: Plants obtain nutrients from air, water and soil. Air is the source of carbon and oxygen. Hydrogen is obtained from water. The remaining thirteen elements are got directly from soil through root absorption.

Question 6.

Compare the use of manure and fertilizers in maintaining soil fertility.

Answer:

Question 7.

Which of the following conditions will give the most benefits? Why ?

(a) Farmers use high-quality seed but do not adopt irrigation or use fertilizers.

(b) Farmers use ordinary seeds, adopt irrigation and use fertilizers.

(c) Farmers use quality seeds, adopt irrigation, use fertilizers and crop protection measures.

Answer: Farmers are benefitted when they use quality seeds, irrigation, fertilizers and crop protection measures (choice c). Ordinary seeds cannot yield very high due to poor quality while quality seeds without necessary inputs yield low.

Question 8.

Why should preventive measures and biological control methods are preferred for protecting crops?

Answer: Preventive measures and biological control methods do not allow any measurable loss in quality and quantity of crops. They also do not cause any degradation of the environment. Cost is also very small. Preventive measures protect crops from pests. Biological control methods eliminate the pests without harming crops and other human interests.

Question 9.

What factors may be responsible for huge losses during storage ?

Answer:

• Abiotic Factors: Excess moisture in grains, dampness and high temperature in storage place.

• Biotic Factors: Insects, mites, rodents, birds, fungi and bacteria.

Question 10.

Which method is commonly used for improving the cattle breeds and why ? (CCE 2011)

Answer: Cross breeding indigenous breeds with exotic breeds. Foreign or exotic breeds have higher milk yield and longer lactation period as compared to indigenous breeds. Therefore, indigenous breeds should be cross¬bred with exotic breeds. The local breeds are hardy and resistant to several diseases. There are two methods of cross breeding — natural and artificial insemination. Artificial insemination is preferred as frozen semen can be transported, required in small quantity and protects the cows from contagious diseases.